Transcript Arab’s Contributions to Cryptology

Cryptography in Ancient Civilizations
Katie Grossman
Tracie Lo
Lauren Schmetterling
Arab Contributions to Cryptology

Wide contributions were not recognized until recent discoveries
of books written by 3 scholars

David Kahn – “Cryptology was born among the Arabs”

Some discoveries are still used in modern cryptography
Factors Behind The Arab
Advancement In Cryptology





Translation
Linguistic Studies
Administrative Studies
Public Literacy
Advanced Mathematics

Concept of zero and Arabic numerals
allowed analytical methods such as
frequency analysis and computation of
letter combinations possible
Al-Kindi (718-786)




Born around 718 in al-Kufa Iraq
Received an education in various
sciences
First to recognize the idea of a
comprehensive dictionary
Wrote the first known book on
cryptology
Al-Kindi’s Contributions

Cryptanalysis techniques



One for normal text
One for poetry
Four methods for normal text




Quantitative techniques
Qualitative techniques
Probable words
Vowel consonant combinations
Al-Kindi Contributions (2)


Tree diagram classification of major
types of cipher
PICTURE HERE
Al Khalil’s Contributions (3)

Most important – statistical techniques


Determined letter frequencies
Set conditions on length of text
required for this statistical analysis
Ibn Adlan



Born in Mosul, Iraq in 1187
Received an education in Baghdad and
later taught in Cairo
Only wrote 4 books, 2 on cryptology
Ibn Adlan’s Contributions


Concept of Variable key for simple
substitution
Detailed study of word spaces



Length should be at least 90 letters long for
frequency analysis.
Categorized letters into 3 groups


Used different symbols for spacing
Common, Medium, Rare
Most remarkable- step by step method of
breaking a cipher
Ibn ad-Durayhim


Born in Mosul in 1312
Most important – in depth description of 8 cipher
systems


Transposition
Substitution







Introduced the idea of what is now known as a Vigenere table
letter addition and omission
Simple cipher mechanisms
Arithmetic cipher
Letter-word substitutions
Substitution for plaintext letters
Use of invented symbols for letters
Mesopotamia
Cuneiform Tablet
http://www.asor.org/IMAGES/tablet.jpg


The oldest known example of Mesopotamian
cryptography is a small encrypted cuneiform tablet
dating about 1500 B.C.E. found on the banks of the
Tigris River.
It used cuneiform sign in their least common syllabic
values, left out the first consonant of several signs,
and used multiple spellings for the same word.
Mesopotamia Cont.

Colophons, stereotyped ending formulas, are used by
Babylonian and Assyrian scribes to sign and date
their clay tablets.

They substituted the standard signs with rare and
unusual ones.

Colophons were later encrypted with numbers
substituting the signs.

Tablet fragments have been found that may be part
of a colophon codebook, the oldest in the world.
India



Artha-sastra by Kautilya discusses the use of
cryptology in political circles.
Officers in institutes of espionage used secret writing
to communicate with their spies while they were in
the field.
It also contain the first reference in history to the use
of cryptanalysis for political gain.
India Cont.



The famous Kama-sutra by Vatsyayana lists secret
writing as one of the 64 arts, or yogas, that should
be known and practiced.
It is called malachite-vikalpa and two types are
described known as kautiliyam and muladeviya.
Kautiliyam is a simple substitution cipher; muladeviya
exists in both written and spoken form.
India Cont.

Ancient Indians also made use of verbal and visual
codes.

Sabhasa is a form of oral code that uses allusive
language.

Nirbhasa is a kind of finger communication or sign
language.

These simple codes are still in use today by Indian
traders and moneylenders.
Incan Cryptography


Series of strands made
from llama or alpaca
hair
Knots on the strings
would symbolize
numbers, letters, and
algebraic functions
Initially for record
keeping, but turned into
a way to exchange
http://www.anthropology.wisc.edu/chaysimire/titulo2/khi
information secretly
pus/quipus.htm
About 700 currently
known
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.


Numerical Usage





About 2/3 of known khipu
document numerical data such
as accounts and financial
transactions
The number zero is represented
by the absence of a knot
Number one is represented by a
figure eight knot
Digits two through nine are
represented by a knot enclosing
the proportionate amount of
turns
Larger numbers are denoted by
combining the smaller digits
http://news.bbc.co.uk/2/hi/americas/4143968.stm
Word Representation






Remaining 1/3 of known khipu represent history,
stories, and messages
Letters cannot be easily deciphered
Context determines meaning
Relative position to other strands and strand color are
vital
Puruchuco palace was an indicator that khipu were
narratives
Not all khipu have been fully deciphered yet
Khipu as Encryption




Estimated that there were many more
khipu
When the Spanish invaded the Incas,
they banned the code
Especially threatening for a dictator
government
Incas could communicate secretly with
each other
Codes of Ancient Greece





All hand written codes
Vary in security
Phiastos Disk- cannot be broken
Scytale- code as simple as they come
Polybius square- one of earliest
substitution
Cryptography in Greek Life




Huge part of life
The Iliad
Aeneas Tacticus- On the Defense of
Fortifications
First civilization to make use of
cryptology in war- scytale, transposition
hilltop distribution
Ancient Europe



Germanic people of
today’s Britain, N.
Europe, Iceland, and
Scandinavia used codes
in runic
Kylver Stone- oldest
runic writing from 400
AD
Rok Stone- written in
another variation of
runic; dates from 800
AD
The Rok Stone
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
http://en.wikipedia.org/wiki/Image:Rökstenen.jpg